


Math Anxiety

by wneleh



Category: Stargate Atlantis
Genre: Episode: s01e02 Rising, Gen
Language: English
Status: Completed
Published: 2013-06-04
Updated: 2013-06-04
Packaged: 2017-12-13 22:59:58
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,456
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/829838
Author URL: https://archiveofourown.org/users/wneleh/pseuds/wneleh
Summary: <blockquote class="userstuff">
              <p>During crises at the SGC, Rodney had at least had the ability to open a frigging Matlab window.</p>
            </blockquote>





	Math Anxiety

**Author's Note:**

> Thanks, cathexys, for the beta!

Everything was going to hell; everything was going to hell, and they were all going to die, and there wasn't a thing Rodney could do about it.

It was time to lay everything out. "The last Zero Point Module is depleted, but limited power," he said. "Turned out that our generators aren't going to hold back an ocean. Life support systems are working but the planet's atmosphere's breathable -- well, notwithstanding the inevitable allergens."

"So now can our naqahdah generators supply enough power to the shield for defensive purposes?" Elizabeth asked.

"Not even close."

Then Sheppard had to open his mouth. "On the surface without a shield? We're target practice."

"I'm acutely aware of that, Major, but thank you for reinforcing it," he snapped back. They were going to die, they were going to die...

He had to make these people see this. "Even with the six symbols Lieutenant Ford provided there are still... " Six factorial - damn, too many, six times five times - shit, he couldn't think... "Hundreds of permutations."

Sheppard looked at him like he was an idiot - yeah, that was the look he was getting - and said, "Seven hundred and twenty."

Of course it was! "Yes. I knew that of course. I'm just surprised you did."

Sheppard ordered them to get busy, and he fled.

\- - - - -

Later, when they didn't die and had had a chance to regroup a bit, Rodney computed up to twenty factorial, in his head, in - well, that couldn't have taken more than 15 seconds. How'd he choked on high school math earlier?

These things had to be automatic, that was it. During crises at the SGC, he'd always had the ability to open a friggin' Matlab window at least. Here, he couldn't be sure they'd even have power for the computers.

To survive here he'd have to memorize stupid _math facts_. More than just party tricks, more than just primes and digits of pi. A waste of brain space on Earth, but here, yeah, he had to know that stuff.

Like trig identities. He never could remember them, but what if he had to use one in an emergency? He needed a list of them, and he needed it now.

Calculus textbooks were good for things like that, but of course he hadn't brought one with him from Earth, because calculus was child's play and besides every lab he'd ever worked in had had at least one floating around.

Five minutes later, he was in the main lab, flipping through Faires and Faires, trying to look nonchalant, but still that Russian-Polish-whatever physicist, Rafi Zamboni (was that right? As names went, that one made no sense) was staring at him. "What are you doing, Doctor McKay?"

"Ah, just a little review," he said. "Never know when we'll need this stuff at the tips of our tongues out here."

"You're reviewing trigonometry? Surely the Canadian educational system..."

"I learned how to sling sines before I lost my first tooth! I could derive all this" - he waved at the page - "given five minutes, a Bic, and a yellow pad, but maybe the enemy isn't handing us those luxuries."

"Well, yes, agreed, it is not always possible to do proofs whenever one would wish," said couldn't-really-be-Zamboni, "But why would you ever need to know what sine of A plus B was, given sine A and sine B? And why not just use a calculator?"

"What if I didn't have one? What if it had been shot out of my hands?"

"Well, then use sine x equals x."

"Only for small values of x." For anything more than a couple of degrees he'd have to use more terms of the Taylor series, which of course he could derive but to survive here he'd better memorize it out to the x-to-the-fifth or sixth terms for sine, cosine, and tangent. And maybe not just the Taylor series about 0. And he'd have to be able to convert to radians, then convert back to degrees for whomever needed the number, which meant dividing and multiplying by fifty-seven point SOMETHING, but what? He'd just have to memorize 180/pi. And be able to multiply and divide multi-digit numbers in his head. Which, yes, he had mental tricks for, but under fire??

"Granted, but still, I repeat, under what circumstances would you possibly need to do this?"

"Well..." There had to be something. Yes! "Say I'm on another planet, or on a landmass here..."

"Why would you leave Atlantis?"

"Shhh. And I was pinned down at night, and needed to fire something at something on a hillside..." Damn, in a vacuum on Earth trajectories were cake, but the equations he knew didn't take air friction into account, and what if he didn't know local gravity? He'd go with something easy... "A laser. I had to fire a laser, in the dark, at a reflector. To let everyone know where we were. Not a problem if I know my location and the reflector is put where it was supposed to go, but what if someone tells me that they actually put the reflector at the top of the hill, twice as high as I'd already accounted for? To get the angle to fire at, I'd need to be able to take an inverse sine in my head."

"Inverse tangent, actually," couldn't-really-be-Zamboni replied. "The hypotenuse changes, the base stays the same."

"Yes, of course you're right," said Rodney. Would not-Zamboni buy it if he said he'd been testing him? Probably not. "But my point is," he continued, "to survive here, I - WE - need to be able to do these sorts of things, quickly and reliably, under any circumstance."

"Leave me out of this," said not-Zamboni. "I'd use the calculator in my watch. And call for help on my radio."

"Ion storm." Finally, something decent had sprung into his brain!

Not-Zamboni nodded, conceding the point, but continuing, "Even if you knew the precise angle upward to aim this theoretical laser, how would you know what direction to point it in? In relationship to local magnetic north?"

"Easy, I'd use a compass."

"I do not think a compass would work during your ion storm."

Rodney slammed the book shut. "Okay, Zam-zam Zamelli..."

"Zelenka, as I have told you several times."

"Zelenka. What would you do?"

"Let the military guard with me, who presumably know what they're doing, use their own methods to hit the target."

"Have you seen those guys?" Rodney sputtered. "Cavemen might do better."

"Then I would hand the laser to the caveman. He probably knows the hillside better than I would. And, anyway, I don't think you're being fair to our military companions. Major Sheppard especially seems quite bright."

Rodney shoved the book back onto the closest shelf. It was past time he ate something anyway.

\- - - - - - - -

It turned out it was near noon, and the mess was reasonably busy. Still, it only took a few minutes for Rodney to grab a sandwich and a Coke, then turn and find Major Sheppard waving him over.

He sank into the chair across from Sheppard. "Um, sorry about Sumner..."

He stopped, then waved his hand in a way that he hoped conveyed sympathy. This was not what he was good at!

Sheppard shook his head a fraction; he didn't seem to be good at this either. "You did good, finding the address of that space gate," he said.

"Yes, um, about that whole thing... why, precisely, did you have six factorial memorized?" he found himself asking.

"I didn't," said Sheppard, smiling - no, smirking. "Calculated it out while you were arguing. You give a guy a lot of time for mental math."

"Oh... well, you're welcome."

"McKay... okay, this is important. I've been doing this a long time. Almost twenty years. You understand what I'm saying? You get used to it. The more you do it - well, it doesn't feel better, but you stay sharper."

"I'm never not sharp!"

"Whatever you say, McKay."

"It's just... " Rodney rotated his plate a little. "There's a lot we need to know instantaneously, I'm finding. I'm planning on working on, you know, my already excellent mental processing speed."

Sheppard nodded. "Couldn't hurt."

"Like, what if I had to compute an inverse tangent in my head."

"Why would you have to compute an inverse tangent?"

"Say, I was trying to fire a laser at a target in the dark, to let you know my position, and I just knew height and horizontal distance."

"Laser?" Sheppard leaned forward. "Cool. What type? HeNe?"

"No, I was thinking just diode-based."

"You'd need something more powerful. And what kind of reflector? Something with some scatter? Or aimed?"

"Well, let's see," said Rodney. "Got some paper?"

From nowhere, Sheppard produced a yellow pad and a Bic.


End file.
